This invention is related to electrical toggle switches. In particular, it is an improved toggle switch that is particularly adapted for service as a miniature or subminiature precision toggle switch.
A toggle switch is a device having a plurality of terminals and means operated by a lever for making and breaking electrical connections between pairs of those terminals. A toggle switch typically has two or more stable states, but the term toggle switch is also applied to switches designed for manual operation by means of a toggle lever and having at least one stable state, with other states involving momentary operation. A toggle switch includes a toggle lever that is mounted to a cover or housing so as to pivot about an axis or the like. A spring is typically placed in contact with the toggle lever to exert a biasing force that will maintain the toggle lever in one or more stable positions, in addition to maintaining or assisting in the maintenance of a force on electrical contacts that are being switched into contact. An example of a typical toggle switch that is known in the art is given in U.S. Pat. No. 3,299,224, entitled "Self-Centering Toggle Switch With Improved Actuator Contact Structure," which is incorporated here by reference as though set forth fully. In the '224 patent, a toggle lever is biased by a flat leaf spring which exerts a force tending to restore the toggle lever to a neutral position when the toggle lever is free to move. A switch having such a spring is prone to wear from friction between the spring and the toggle lever. The leaf spring is also best adapted to the application of a force to restore the toggle lever to a neutral position, and is less effective or is ineffective in applying a force to maintain the toggle lever in a position off the neutral position. Switches made according to the teachings of the '224 patent also tend to require more components and to be more difficult to manufacture than the improved toggle switch of the present invention.
A different type of spring for applying a restoring force to a toggle switch is shown in U.S. Pat. No. 3,571,545, entitled "Toggle Switch With Pivotal Shorting Bar Bridging Stationary Contact Pins, And Slidable Cam Block Detent Means." This patent teaches a shorting bar placed on the toggle lever, with a slidable cam biased against a portion of the toggle lever by a coil spring that is coaxial with the toggle lever. The switch of the '545 patent has the disadvantage of making electrical contact with the shorting bar placed on the toggle lever. This requires that at least a handle of the toggle lever be made of an insulating material so that there is no danger of electric shock to a user of the switch.
U.S. Pat. No. 3,581,003, entitled "Toggle Switch," which is incorporated here by reference as though set forth fully, teaches a toggle switch in which a restoring force for the toggle lever is supplied by a coil spring that is fitted in a hole in the toggle lever that is coaxial with the lever. This results in a coil spring of a relatively small diameter. The smaller coil spring of the '003 patent is more easily broken than a coil spring such as the one disclosed and claimed in the present invention that is large enough in diameter to enclose the toggle lever. For this reason, a toggle switch made according to the teaching of the '003 patent typically has a shorter service life than a toggle switch made according to the teachings of the present invention. The larger spring may also exert a greater force for toggle activation.
It is an object of the present invention to provide a better electrical toggle switch.
It is a further object of the present invention to provide a more reliable miniature or subminiature electrical toggle switch.
It is a further object of the present invention to provide a miniature or subminiature electrical toggle switch that is easier to manufacture than toggle switches that are presently known.
It is a further object of the present invention to provide a miniature or subminiature electrical toggle switch that can be manufactured so as to function in one of a plurality of maintain or momentary combinations by changing a single part during manufacture.
It is a further object of the present invention to provide a miniature or subminiature electrical toggle switch in which a toggle lever pivots in its housing on a spherical portion of the toggle lever.
It is a further object of the present invention to provide a terminal for a miniature or subminiature electrical toggle switch that has an electrical contact surface formed by placing a spherical ball of a material that is appropriate for electrical contacts in a cylindrical aperture in the terminal and then heading the spherical ball nearly flat while peening it into place.
It is a further object of the present invention to provide a miniature or subminiature electrical toggle switch in which forces tending to restore the switch to a maintained position from a momentary position and also to apply contact pressure are obtained from a single coil spring that encloses a toggle lever.
Other objects will become apparent in the course of a detailed description of the invention.